Storage System and Methods

ABSTRACT

A storage system includes a rack with a plurality of layers, each layer including an aisle and a plurality of rows extending from the aisle defining storage locations for items. A shuttle usable with the rack includes a first cart movable along the aisle and a second cart configured to be carriable by the first cart and to be movable along a row. The second cart is configured to carry an item between the first cart and the storage locations. A conveyor is located on one of the first or second carts to move the item onto or off the first cart. Related methods of storing and/or retrieving items from a rack are also disclosed. A rack system is disclosed and is readily assembled without welding, transferring loading so that the weight of the rack and any item stored therein is supported by the upright elements via support brackets.

RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. §119 of U.S.Patent Application No. 61/561,895, filed Nov. 20, 2011, whichapplication is incorporated herein by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to storing and retrieving itemsin rack based systems.

BACKGROUND

Warehousing and distribution facilities have grown in importance in thesupply chain in recent years. In such facilities, large warehouses areused to collect and store many types of goods at a central location forshipment by truck to one or more locations, typically retail locations.Goods may be stored in the warehouse by pallet load or individually, andgoods may be shipped either by uniform pallet, mixed pallet, orotherwise. To maximize efficiency, goods are often stored in verticalrack based systems, multiplying the amount of goods that can be storedin a given amount of square footage.

Some systems, sometimes known as high density or ultra-high density racksystems, store pallets of goods in a large, multi-layer rack. Palletsare stored according to known identifiers such as SKU numbers or thelike and kept track of by a computer-based system. As pallets of goodsare stored in the system, the related identifiers are noted and storedin a computer memory or the like so that when the goods are desired,they can be retrieved.

Automated systems of this type use carts that place the goods in therack and retrieve the goods when desired. Such automated systems provideefficiency in terms of floor space usage, as well as quick loading andretrieval of goods with low need for manual attention or monitoring.Various cart-based rack systems have been proposed, with one or morecarts that travel from a staging area to a storage area to place andretrieve goods. Existing cart-based systems and related rack structuresprovide acceptable storage capabilities. However, as rack systems becomelarger, improvement in cart functionality and efficiency, as well as inrack design to handle larger systems, would be welcome.

SUMMARY

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be apparent from the description, or maybe learned through practice of the invention.

According to certain aspects of the present disclosure, a system forstoring and retrieving items includes a rack with a plurality of layers,each layer including an aisle and a plurality of rows extending from theaisle. The items are storable in storage locations along the rows. Eachaisle has a loading position at one end and transfer positions locatedalong the aisle adjacent ends of the rows. A shuttle is located on eachlayer. At least one of the shuttles is a dual shuttle including a firstcart movable along the aisle between the loading position and thetransfer positions and a second cart configured to be carried by thefirst cart between the loading position and the transfer positions. Thesecond cart is movable in either direction between a transfer positionand a storage location along a row while carrying an item. A conveyor islocated on the dual shuttle operable when the first cart is at theloading position to move the item onto or off the first cart. Variousoptions and modifications are possible.

According to certain other aspects of the invention, a system forstoring and retrieving items includes a rack including a plurality oflayers, each layer including an aisle and a plurality of rows extendingfrom the aisle. The items are storable in storage locations along therows. Each aisle has a loading position at one end and transferpositions located along the aisle adjacent ends of the rows. A shuttleis located on each layer. At least one of the shuttles is a dual shuttleincluding a first cart movable along the aisle between the loadingposition and the transfer positions and a second cart configured to becarried by the first cart between the loading position and the transferpositions. The second cart is movable in either direction between atransfer position and a storage location along a row while carrying anitem. A conveyor is located on the first cart operable when the firstcart is at the loading position to move the item onto or off the firstcart. A lift is located substantially adjacent the rack for liftingitems to the respective loading positions for the layers, the liftincluding a platform having a conveyor for moving items off the liftplatform and toward the loading positions of the respective layers.Various options and modifications are possible.

According to certain other aspects of the invention, a system forstoring and retrieving items includes a rack including a plurality oflayers, each layer including an aisle and a plurality of rows extendingfrom the aisle. The items are storable in storage locations along therows. Each aisle has a loading position at one end and transferpositions located along the aisle adjacent ends of the rows. A shuttleis located on each layer. At least one of the shuttles is a dual shuttleincluding a first cart movable along the aisle between the loadingposition and the transfer positions and a second cart configured to becarried by the first cart between the loading position and the transferpositions. The second cart is movable in either direction between atransfer position and a storage location along a row while carrying anitem. The second cart has a raisable top platform, a first motor formoving the second cart along the rows and a second motor for selectivelyraising the top platform to lift an item. A conveyor is located on thedual shuttle operable when the first cart is at the loading position tomove the item onto or off the first cart. A lift is locatedsubstantially adjacent the rack for lifting items to the respectiveloading positions for the layers, the lift including a platform having aconveyor for moving items off the lift platform and toward the loadingpositions of the respective layers. Again, various options andmodifications are possible.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention is set forth inthe specification, which makes reference to the appended figures, inwhich:

FIG. 1 shows a perspective view of a rack system according to certainaspects of the disclosure;

FIG. 2 shows a side view of the rack system of FIG. 1;

FIG. 3 shows a closeup of a portion of the rack system as in FIG. 2

FIG. 4 shows an end view of the rack system of FIG. 1;

FIG. 5 shows a closeup of a portion of the rack system as in FIG. 4;

FIG. 6 shows a perspective view of a portion of the rack system of FIG.1 showing a bracket portion;

FIG. 7 shows an exploded perspective view of the elements in FIG. 6;

FIG. 8 shows a perspective view of a dual shuttle useful in the racksystem of FIG. 1;

FIG. 9 shows a perspective view of a first (aisle) cart of the dualshuttle with a second (row) cart removed;

FIG. 10 shows a closeup perspective view of a portion of the aisle cartshowing a chain conveyor;

FIG. 11 shows a perspective view of the aisle cart with top housingelements removed for clarity to show internal drive elements;

FIG. 12 shows a perspective view of a row cart according to certainaspects of the disclosure;

FIG. 13 shows a perspective view of the row cart of FIG. 12 with its topplatform removed to display internal elements;

FIG. 14 shows a top view of the row cart of FIG. 12 with the topremoved;

FIG. 15 shows a top view as in FIG. 14 with lifting bars furtherremoved;

FIG. 16 shows a side diagrammatical view of the row cart of FIG. 12showing the top platform in a raised orientation;

FIG. 17 shows a side diagrammatical view as in FIG. 16, with the topplatform in a lowered orientation;

FIGS. 18-22 show sequential schematic views of a pallet loading functionusing a rack system as in FIG. 1 and a dual shuttle as in FIG. 8;

FIG. 23 shows a perspective view of a portion of an aisle cart showingelectrical contacts for powering the aisle cart;

FIG. 24 shows a perspective view of the portion of the aisle cart ofFIG. 23 contacting an electrified rail;

FIG. 25 shows a perspective view of an aisle cart showing electricalcontacts for powering a row cart; and

FIG. 26 shows a perspective view of a bottom portion of a row cartshowing electrical contacts for receiving power from the electricalcontacts on the aisle cart shown in FIG. 25.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

FIGS. 1-7 show an example of a rack 50 according to certain aspects ofthe disclosure. It should be understood that rack 50 as illustrated isbut one example constructed using the present teachings. For example,rack 50 could be much larger than that shown. Also, multiple racks couldbe employed in a given location. Therefore, rack 50 could be a componentof a larger combined automated storage system. For example, FIGS. 18-22,discussed below with reference to use of the disclosed structures, showstwo side by side racks 50 substantially larger than that illustrated inFIG. 1. FIGS. 20 and 21 also show related equipment such as lifts andconveyors that will also be discussed below as part of an overallautomated system. Therefore, it should be understood that the full scopeof the invention includes all such modifications, extensions andvariations.

As shown in FIGS. 1-7, rack 50 includes a plurality of upright elements52 arranged in a grid, a plurality of first horizontal elements 54extending in a first direction to connect adjacent upright elements, anda plurality of second horizontal elements 56 extending in a seconddirection perpendicular to the first direction. Rack 50 includes anumber of layers 58 formed by such intersecting horizontal elements 54and 56. Struts 60 may also be provided to stiffen the structure.

The upright elements 52 and horizontal elements 54 and 56 are connectedvia fasteners attached ultimately to a plurality of support brackets 62.Each upright element 52 has a plurality of support brackets 62 mountedto it at different heights with each height corresponding to a layer 58.Support brackets 62 are attached to upright elements 52 by fasteners 64without welding (see FIG. 7). Also, mating tabs 66 and slots 68 may beprovided for additional alignment and support assistance both duringassembly and use.

Each second horizontal element 56 forms one side of a portion of a trackfor a row 88 to be travelled by a row cart 104, as will be describedlater. Accordingly, opposing elements 56 mounted to adjacent brackets 62form such a row track (see FIG. 3). Second horizontal elements 56 areattached to brackets 62 via fasteners 70 without welding (see FIG. 7).Brackets 62 may have flanges 72,74,76 for rigidity and for aligning andattaching second horizontal elements 56, and flange 77 for aligning andattaching to upright elements 52.

First horizontal elements 54 provide spacing and support for elementswithin rack 50 and may be attached to upright elements 52 with fasteners78 and to flange 79 of brackets 62 with additional fasteners 80. Endbrackets 82 at ends of rack 50 can be modified versions of brackets 62,designed to accept only one track element 56, if desired. Again, nowelding is required. When goods are stored in rack 50, the goods arestored in discrete predetermined locations on rows 88 formed by secondhorizontal elements 56. Due to the fastened-together structure of rack50, the weight of the rack and the stored items is transferred to andsupported by upright elements 52 substantially via brackets 62. Each ofthe above elements can be formed of a metal such as steel or aluminum,can be painted, powder coated, etc. as desired. Due to the widevariation in potential sizes and loading, one skilled in the art canreadily select dimensions and materials for the elements and fastenersto meet a given application need.

Typically, items to be placed on rack 50 will be moved to and within therack on a platform 84 such as a wood, polymer, or metal pallet, althoughother platforms could be used, and platforms could be avoided wherelarge or unitized items are being moved. Accordingly, mention of movingloads, pallet loads, items or goods herein is intended to include movingitems or goods on platforms or without platforms.

Items are moved within rack 50 in each layer along an aisle 86 and thenalong one of the rows 88. Various shuttle devices can be used for suchmovement into and out of the rack according to certain aspects of thedisclosure (see aisle carts 102 and row carts 104 in FIGS. 2-5,discussed in greater detail below). Along aisle 86, horizontal elements54 may be replaced with or supplemented by track elements 90 to transferthe shuttle device along the aisle. As discussed below, power can beprovided to the shuttle carts 102 and 104 in various locations in therack.

FIG. 8 shows one example of a dual shuttle 100 useful in the presentsystem and methods. As shown, dual shuttle 100 includes a first (aisle)cart 102 (FIGS. 8-11) and a second (row) cart 104 (FIGS. 8 and 12-17)that can be carried on or driven off the aisle cart. Track portions 106on aisle cart 102 are sized to complement track sections 56 of rack 50allowing row cart 104 to drive on or off the aisle cart.

Aisle cart 102 includes two motors 108 and 110. Motor 108 drives aislecart 102 up and down track elements 90 of the respective aisle 86 inwhich the cart is located. Motor 110 drives a conveyor 112 on aisle cart102 for loading and unloading items onto the aisle cart. It should beunderstood that conveyor 112 could also be located on row cart, ifdesired. Also, it should be understood that conveyor 112 can place itemsdirectly onto aisle cart 102, or can place items on row cart 104 nestedwithin the aisle cart, both of such modes being considered moving theitems onto the aisle cart and/or moving the items onto the dual shuttle.Accordingly, as discussed in greater detail below, variousconfigurations and modes of operation are possible within the scope ofthe present invention.

Both motors 108,110 can be powered by an energy storage device such as abattery, capacitor, a combination of a battery and capacitor, or thelike charged by suitable electrical connections (see FIGS. 23-26) inrack 50. If desired, even though an energy storage device that wouldoutput DC current could be employed, motors 108,110 can be AC motors,used with an inverter. Use of such AC motors with an inverter mayprovide a less expensive alternative than use of a DC motor.

Also, as discussed below, aisle cart 102 can receive three-wire singlephase or three-phase AC power directly from track elements 90 via anelectrified rail/wiper system. Use of such direct powering allows aislecart 102 to be constantly and fully electrified, without need forcharging. Also, the weight and space used by the energy storage devices,inverter, etc., can be eliminated from each aisle cart 102. Becauseaisle carts 102 each traverse only one dedicated aisle 86, electrifyingthe aisles with a track (see FIGS. 23-26) and wiper contact interface isa cost effective solution for powering aisle carts 102.

Motor 108 is connected to a gear box 114 with an output gear 116 thatdrives a chain 118 that drives an input gear 120 of a shaft 122. Wheels124 are mounted to shaft 122. Wheels 126 mounted on shaft 128 may beidlers. By operating motor 108 in one way or the other, wheels 124 arerotated clockwise or counterclockwise, thereby moving aisle cart 102 upand down an aisle in the rack. If desired an encoder or the like may beattached to one of the wheels, shaft, motor, gearbox, etc., to providefeedback and control as to location of cart 102 along the aisle.Alternatively or in addition, external detection devices such as opticalor laser detectors, rfid elements, etc., may be used for positionsensing and control. Cart 102 may include a wireless communicationdevice (not shown) for communicating with a controller for the system toreceive signals and provide feedback as to desired tasks, locations,etc.

Motor 110 is connected to a gearbox 129 having a drive gear 130 thatdrives a chain 132. An input gear 134 of shaft 136 is rotated by chain132. Two output gears 138 on shaft 136 drive chains 140 ofloading/unloading conveyor 112. Accordingly, driving motor 110 one wayor the other causes chains 140 to move one way or another. Such motionof chains 140 can be used to pull items onto or push items off aislecart 102 when desired. As shown in FIG. 8, when row cart 104 is nestedwithin aisle cart 102 with its top surface 142 in a retracted (notraised) position, chains 140 are higher than the top surface. Therefore,movement of chains 140 of loading conveyor 112 with row cart 104 inplace allows a load, pallet, etc., to be moved onto aisle cart 102without interference by row cart 104. However, carts 102 and 104 couldbe configured or operated differently, so that chains 140 move a loadonto cart 104, either initially or after lifting top surface 142 of cart104, as discussed below. Therefore, although the description hereinshows pallets 84 being supported on chains 140 located on aisle carts102, the pallets could at times be supported by row carts 104 when therow carts are on aisle carts.

An example of a row cart 104 is shown in FIGS. 12-17. Row cart 104includes a frame 144 and movable top surface 142 forming a platform forreceiving loads. Within frame 144 are two motors. Motor 146 drives cart104 along rows 88 and motor 148 moves top surface 142 up and down. Motor146 drives a gearbox 150, an output gear 152 and a chain 154. Chain 154drives an input gear 156 of shaft 158 on which driven wheels 160 aremounted. Output gears 162 drive chains 164 that drive input gears 166 ofshafts 168 to drive driven wheels 170. Accordingly, driving motor 146 inone direction or another rotates wheels 160 and 170 clockwise orcounterclockwise, thereby moving row cart 104 along a row 88, or onto oroff aisle cart 102.

Motor 148 lifts top surface 142 off cart 104 when desired to lift anitem off either loading conveyor 112 of cart 102 or a position withinstorage rack 50. Motor 148 drives a gearbox 172 and an output gear 174to drive a chain 176. Chain 176 drives input gear 178 mounted to shaft180, to which camming elements 182 are attached for rotation with shaft180 around a substantially horizontal axis. Wheels 184 are idlers thatmove independently of shaft 180. Camming elements 182 include lifters186 which may be in the form of a wheel or the like. Pins 188 and bars190 connect camming elements 182 with similar camming elements 192 atthe other end of frame 144. If desired, a track element 194 (see FIG.14, removed in FIG. 15 for clarity) may extend between camming elementsfor attachment to or contact with surface 142 when lifters 186 areactivated. Wheels 196 are idlers and an encoder 198 may be attached forrotation with one of the wheels 196 or elsewhere to track position, asdiscussed above. Use of eight wheels on each row cart 104 assists inkeeping the row cart stable when driving between row cart 102 and a row88.

FIGS. 16 and 17 show schematically the lifting of top surface 142 offframe 144 of row cart 104. As shown, rotation of motor 148 a smalldistance causes chain 176 to move camming elements 182 and cammingelements 192 (via bars 190). Accordingly, wheels 186 are moved so as toraise or lower top surface 142 via track elements 194. FIG. 17 shows thetop surface 142 below the raised level 200, which is higher than thelevel 202 of loading conveyors 112 on aisle cart 102 when the carts 102and 104 are nested, and higher than the level of track portions 56 onwhich loads are placed.

It should be understood that the gears, chains, etc., used to drive thevarious components in carts 102 and 104 could be modified in variousways. For example, multiple motors could be used instead of connectingmultiple driven items by chains and gears. Therefore, the driving andlifting functions of the carts could be achieved in various ways withinthe scope of the invention.

Cart 104 may be driven via an energy storage device 204 such asbatteries, capacitors, combinations or batteries and capacitors, or thelike. Motors 146, 148 may be DC motors or may be AC motors if aninverter 206 and frequency converter 208 is used (all schematicallyshown in FIG. 14). For example, running a battery at 24 VDC through aninverter to create 230 VAC and a frequency converter to allow use ofcommon 400 VAC motors can provide cost and maintenance savings.Batteries rated in the range of 24 Amp-hours provide suitable power totravel along rows 88 with loads with the duration of charging providedby contact with aisle cart 102, as described below. If energy storagedevice 204 includes a capacitor, it may be an ultra-capacitor providinga substantially equivalent output. Capacitors provide the benefit ofquick charging of row cart 104, as described below, and accordingly canprovide for alternate modes of operation.

Power can be provided to the dual shuttle 100 in various ways. Forexample, an electrified rail may be added along aisles 86 within rack 50to constantly power aisle cart 102 or charge the energy storage deviceof the aisle cart, if desired. Since there are many fewer aisles 86 thanrows 88, adding electrification to aisles only can be cost effective insome applications. Alternatively, charging could be provided at only onelocation or some locations along aisles. Such structure would require anenergy storage device within aisle cart 102.

Similarly, row cart 104 can be charged via an electrified rail or viacharge from a given location. If desired, aisle cart 102 and row cart104 may have electrical contacts so that aisle cart can maintain chargeon the row cart. As there are many more rows 88 than aisles 86, addingrail/wiper electrification to all of the rows while simplifying the rowcarts 104 so as to eliminate the energy storage device and relatedelectronics may not be as cost effective as employing more electricallycomplicated row carts (with batteries or capacitors, for example)charged via aisle carts 102. However, if capacitors are used in rowcarts 104, placing a single charge contact located at an end of a rowadjacent the aisle may be a suitable mode of charging the row carts.Capacitor charging occurs in a matter of seconds, and each time a rowcart 104 passes the end of a row, it could pause just long enough forcharging before or after moving onto or off the aisle cart 102, orcharging could occur while the row cart is idle and the aisle cart iselsewhere. Alternatively, the capacitor charging contact in the rowcould be lengthy enough to charge row cart 104 while moving (withoutpausing) to make the system more efficient in terms of load moves perhour. Electrically connecting the carts 102 and 104 so that row carts104 are charged by aisle carts 102, and aisle carts are charged via anelectrified rail, may be the most cost effective solution in someapplications, particularly those with battery powered row carts.However, it should be understood that various methods and systems ofelectrical delivery and usage are possible within the present invention.

FIGS. 18-22 show diagrammatically a large system, using two individualracks 300, much larger than rack 50, arranged side by side with a numberof pieces of auxiliary equipment. For clarity, certain structure of theprevious figures has been eliminated from FIGS. 18-22 so as to focus onoverall layout and function.

As shown, racks 300 each include two lifts 302, one on either side of anaisle 303. Use of two lifts 302, particularly in a large system,optionally allows greater throughput. Each lift 302 includes a liftplatform 304 onto which items 306 are placed, as illustrated goods/items308 on pallets 310. Each lift platform 304 is moved up and down rack 300along a frame 312 between layers 314 (in this case six, layers).

A system 316 of feed and delivery conveyors can be provided adjacentlifts 302 and racks 300. As shown, first conveyors 318 adjacent lifts302 fed by second conveyors 320 can transfer items to and from the liftplatforms 304. An array of third conveyors 322 can be provided alongwith a common conveyor 324. Third conveyors 322 can be used withindividual vehicles, for example, for loading and unloading. Commonconveyor 324 can use a transfer cart 326 similar to aisle cart 102 forreceiving items from one of the third conveyors 322 and distributing itto one of the second conveyors 322 (or vice versa). The variousconveyors disclosed can be driven or idler rollers, belt conveyors,chain conveyors, etc., as desired, with appropriate motor drives, invarious possible orientations and arrangements. The logic and decisionmaking for storage and retrieval of items in racks 300 can be controlledby various types of systems available from various sources, includingITW Warehouse Automation, using programmable logic controllers or thelike. Accordingly, it should be understood that various differentsystems 316 for feed and delivery of items, as well as logic andmanagement of items are all within the scope of the present invention.

Preferably, lift platforms 304 each include a motor driven conveyor 328with at least one chain or belt similar to conveyor 112 on shuttle carts100. Lift conveyors 328 can be used to move items onto or off liftplatforms 304 when desired. If some spacing exists between lifts 302 andaisles 303, that can be taken up by a buffer conveyor 330. Each bufferconveyor 330 can also have one or more motor-driven conveyors 331 suchas a chain, belt or the like, however the buffer conveyors could beidlers between the driven lift platform conveyors 328 and the aisleswhere shuttles 100 are located. If desired, all of the lift platforms304, buffer conveyors 330 and shuttles 100 (aisle carts 102 and/or rowcarts 104) may include driven chain or belt conveyors on top surfacesfor selectively moving items. Accordingly, a lift 302 can place an itemon a buffer conveyor 330 in an upper layer when aisle cart 102 is not ina loading position at the end of aisle 303 next to the buffer conveyor,and then the lift can return to the base layer to retrieve another itemwhile the aisle cart returns to retrieve the placed item. Multiple itemscan be located on a given buffer conveyor 330 while the dual shuttlecarts 102/104 do their work placing other items, or while waiting forthe lift 302 to return to pick them up to deliver them out of rack 300.If buffer conveyor 330 is used and is also motorized, when aisle cart102 returns to the loading position, buffer conveyor 330 and aisle cartconveyor 112 can be activated simultaneously to pull the item onto theaisle cart. By loading aisle cart 102 using an onboard conveyor 112, rowcart 104 need not be sent off and back on the aisle cart for loading,which saves time and energy within the row cart's batteries. Use ofand/or motorizing buffer conveyor 330 further assists in this efficiencybut is not required in all applications.

For example, in some conventional applications without an onboardconveyor such as conveyor 112 where a row cart leaves an aisle cart at aloading position of a rack system adjacent a lift or the like, an amountof time in the range of about 22-25 seconds is required to move a loadfrom the lift to the aisle cart. In this time, the row cart must startmoving off the aisle cart, accelerate, travel, decelerate, stop movingat the lift, pick up a load, start moving off the lift, accelerate,travel, decelerate, stop moving at the aisle cart, and then lower theload into the aisle cart. The time used by such activity impacts thenumber of pallet moves per hour. In some large rack systems with1000-1500 items stored in approximately 50 sets of rows along an aisle,shuttle systems that load aisle carts using row carts as above make inthe range of 20-25 pallet moves per hour. Such aisle cart loadingactivity also causes the row cart to be off the aisle cart twice pereach pallet move (receiving the pallet and depositing the pallet),thereby using more energy per pallet move, causing a larger, heavierbattery to be needed, due to both more activity and less opportunity forcharging per pallet move.

Using the disclosed shuttle 100 with the loading/unloading conveyor 112located on one of carts 102,104, the time needed to load a pallet at aloading position adjacent a lift in a system of the above size isreduced to the range of less than about 15 seconds and may be in therange of about 5-7 seconds. Therefore, if 15-20 seconds are saved perpallet move using the disclosed shuttle 100 with loading/unloadingconveyor 112, several more pallet moves per hour are possible renderingthe entire system more efficient and/or allowing the size of the rackserviced by a shuttle to be enlarged.

Efficiency in terms of pallet moves per hour can also be achieved bydriving carts 102 and 104 faster than in conventional systems, of coursewithin limits so as to not mishandle loads. For example, driving rowcarts 104 at a speed in the range of 4.0 m/s vs. a speed of 2.25 m/s asin certain available systems provides further pallet move per hourimprovement. Acceleration and deceleration can be increased as well tothe range of 0.5 m/s² from 0.17 m/s² as in certain available systems.

Accordingly, for a rack system sized as above (1000-1500 items per layerin 50 sets of rows along an aisle), pallet moves can be increased to arange of above 30 pallet moves per hour, and further to a range of 40-45or greater pallet moves per hour, through use of the onboardloading/unloading conveyor 112 and driving row carts 104 and/or aislecarts 102 faster. Therefore, pallet moves per hour for a given size rackcan be more or less doubled using the various teachings of the presentdisclosure.

Further, simultaneous separate operation of row and aisle carts at leastsome of the time can help achieve some additional efficiency benefits.For example, if row carts 104 are not located on aisle carts 102 forcharging while the aisle carts return from a row to theloading/unloading area with a load (or to get a load), the row carts canbe active simultaneously in a row to get or return a load. Simultaneousseparate operation of row and aisle carts therefore can provide evenfurther efficiency benefits or as many as 60 pallet moves per hour ormore, when used with the above improvements as well. Such simultaneousoperation may be achieved by allowing row carts 104 to be chargedsometimes or always off aisle carts 102, for example in rows.Alternatively, such simultaneous operation could occur on a more limitedbasis if even if charging is done only on aisle carts 102. It should beunderstood that not all aspects of the disclosure need be used or usedto the extent mentioned above in all applications within the scope ofthe invention. Further, improvement in function, stability, operation,etc., does not require an improvement in pallet moves per hour in allaspects of the invention.

FIGS. 18-21 show the use of lifts 302 and buffer conveyors 330 to getitems onto dual shuttles 100 (including nested carts 102 and 104) at theloading position. FIG. 22 shows that dual shuttle 100 has traveled downan aisle 303 to a desired row 332. Row cart 104 has raised its uppersurface 142 to lift the item off conveyors 112 of aisle cart 102 and hasleft the aisle cart to deliver the item to a desired location in the row332. Aisle cart 102 may wait for row cart 104 or may return to the liftarea for another load while the row cart operates. After reaching thedesired location, row cart 104 will lower its upper surface 142 to placethe item. Row cart 104 may then return down the row to nest within aislecart 102, if the aisle cart is waiting for the row cart, or to wait forthe aisle cart to return. Aisle cart 102 will then either move downaisle 303 to a different row to retrieve an item from storage, sendingrow cart 104 out to do so, or return to the loading area at the end ofthe aisle to obtain an additional item to place into storage, or allowrow cart 104 to take a load to the present row or a different row if theaisle cart had left to get another load while the row cart wasoperating. These patterns repeat as controlled by the master controllerof the entire automated warehousing system, as desired.

The retrieval of items from the rack is essentially the same pattern inreverse. Row cart 104 gets a load, carries it to the aisle cart 102, andthe two carts return nested to the loading/unloading position at the endof the aisle. At that point, conveyor 112 drives the load off theshuttle 100.

As stated, to achieve greater pallet move per hour efficiency, carts 102and 104 need not always be nested when aisle cart 102 moves between tothe rows and the loading/unloading position at the ends of the aisles.Therefore, during a storing operation, as soon as row cart 104 leavesaisle cart 102 with a load, the aisle cart could return to the loadingarea to get another load. Aisle cart 102 could then return to retrieverow cart 104, which would drive onto the aisle cart beneath the secondload. If the second load is to be placed in the same row, row cart 104could place the load in the row, and the process could repeat. Similarfunction can occur during retrieval, as aisle cart 102 can be moving aretrieved load down the aisle to the loading/unloading position whilerow cart 104 is moving along a row to get the next load, either in thesame row as previously or a different row (as dropped off by the aislecart).

However, operation of the row cart and aisle carts separately in suchfashion reduces the nested time of the row cart on the aisle cart. Ifrow cart 104 is to be powered and charged by contact only with aislecart 102, only a limited, defined amount of usage time off the aislecart is advisable before the energy storage device in row cart 104 wouldbe drained. The overall control system can optionally monitor andcontrol such operation if needed to limit such operation in variousways, such as to allow only a certain number of row cart trips per hour,to require a certain amount of nested time per hour, to allow for only acertain number of successive row trips or row trips only a certaindistance from the loading area or from each other, etc. Such limitationsmight not be needed if row carts 104 are charged or powered by wipingcontact with electrified rails on rows or other method apart fromnesting on aisle carts 102. Row carts 104 can operate more independentlyfrom aisle carts 102 if they have a capacitor or ultra-capacitor basedenergy storage device, as such can be charged quickly by charging padsin the rows, either instead of or in addition to charging on the aislecarts.

FIGS. 23-26 show one example of electrical connections that could beused to power the aisle and row carts. As shown, aisle cart 102 caninclude an electrical contact 400 in the form of a brush, wiper, etc.,for receiving power from an electrified track 402 on the side elements90 forming part of the aisle cart track. As shown, brush 400 has fourcontacts 404, 406, 408, 410, that can be used to contact individualelements 412, 414, 416, 418 on track 402 for three-phase power AC supplyplus ground. If desired, single-phase AC power could also be providedwith positive/negative connections plus ground. Using a slidingconnection in this fashion may be simpler than providing a cableconnection to aisle cart 102 in some applications, although that couldalso be employed as an option.

A contact 420 on top of aisle cart 102 includes two spring-loadedelements 422, 424 for contacting two plates 426, 428 on an electricalconnector portion 430 of row cart 104. The storage element (batteryand/or capacitor) on row cart 104 can be charged whenever it is locatedon aisle cart 102 via contact between elements 422, 424 and plates426,428. The location of elements 422,424 and plates 426,428 can bereversed between the carts. Alternatively, instead of placing elements422, 424 (or 426,428) on aisle cart 102, such elements could be placedin the rack, for example in the center of the end of each row adjacentthe aisle. Such location could be particularly useful if capacitors orultra-capacitors are employed as an energy storage device within carts104. As a further alternative, row carts 104 could employ a wiper andtrack system as disclosed for aisle carts 102 above for direct poweringor charging or an energy storage device. Various devices suitable formaking the electrical connections between the aisle cart track 90 andaisle cart 102, and between the aisle cart and row cart 104 or rack, areavailable from Vahle Electrification Systems.

Use of such power delivery systems allowing the row carts 104 to becharged on the aisle carts 102 and/or within rack, while also drivingthe row carts off the aisle carts to go up and down rows and not to haveto load or unload at the loading locations at the lift platforms 304,provides various benefits. First, the system can move more loads perhour, as using the lift conveyor 328 and optional buffer conveyor 331chains to move loads between the lifts and dual shuttle is generallyfaster than driving the row cart 104 back and forth off the aisle cart102 to do so. Also, keeping the row cart 104 on the aisle cart 102 formore time provides more time within a duty cycle for charging and/orallows for use of a smaller storage device in the row cart, therebypotentially providing cost savings for the storage device and the motorused to drive it. However, within certain aspects of the invention evenif a row cart 104 is driven off an aisle cart 102 to load and unloaditems at a loading/unloading position the end of the aisle, otherdisclosed structures and methods above provide other benefits within thescope of the present invention.

In view of the above, a rack, a dual shuttle, an aisle cart, a row cart,and an automated warehousing system are disclosed having variousbenefits. Further, methods of use of such items are disclosed. Thesystems may allow for a more rapid storage and retrieval of items, mayemploy smaller and more efficient carts, and may be easier to assembleand use. Numerous benefits are provided by the various disclosed subjectmatter curing at least some of the drawbacks posed by conventionalsystems.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

We claim:
 1. A system for storing and retrieving items comprising: arack including a plurality of layers, each layer including an aisle anda plurality of rows extending from the aisle, the items being storablein storage locations along the rows, each aisle having a loadingposition at one end and transfer positions located along the aisleadjacent ends of the rows; a shuttle on each layer, at least one of theshuttles being a dual shuttle including a first cart movable along theaisle between the loading position and the transfer positions, the dualshuttle including a second cart configured to be carried by the firstcart between the loading position and the transfer positions, the secondcart movable in either direction between a transfer position and astorage location along a row while carrying an item; and a conveyorlocated on the dual shuttle operable when the first cart is at theloading position to move the item onto or off the first cart.
 2. Thesystem of claim 1, wherein the conveyor is on the first cart.
 3. Thesystem of claim 1, wherein the second cart is located on the first cartwhen the conveyor is operated.
 4. The system of claim 1, wherein theconveyor moves the item directly onto the first cart.
 5. The system ofclaim 1, including a lift substantially adjacent the rack for liftingitems to the respective loading positions for the layers.
 6. The systemof claim 5, wherein the lift includes a platform having a conveyor formoving items off the lift platform and toward the loading positions ofthe respective layers.
 7. The system of claim 6, wherein each layer ofthe rack includes a conveyor adjacent the loading position fortransferring items from the lift platform to the loading position. 8.The system of claim 1, wherein the first cart has a first motor formoving the first cart along the aisle and a second motor for driving theconveyor.
 9. The system of claim 8, wherein the first and second motorsof the first cart are AC motors.
 10. The system of claim 1, wherein thesecond cart has a raisable top platform, a first motor for moving thesecond cart along the rows and a second motor for selectively raisingthe top platform to lift an item.
 11. The system of claim 10, whereinthe top platform can be lifted to remove an item from the first cartwhen the first and second carts are located at a transfer position sothat the second cart can carry the item to a storage location in therespective row.
 12. The system of claim 10, wherein the top platform canbe lifted to retrieve an item from a storage location in a row so thatthe second cart can carry the item to the first cart, the first cartthen carrying the item to the loading position for transfer out of therack.
 13. The system of claim 10, wherein the top platform is raised bya camming device that rotates around a horizontal axis.
 14. The systemof claim 10, wherein the first and second motors of the second cart areAC motors.
 15. The system of claim 1, wherein the second cart has anenergy storage device for storing energy used to power the second cart.16. The system of claim 15, wherein the energy storage device in thesecond cart is a charged via electrical contact between the second cartand the first cart.
 17. The system of claim 15, wherein the energystorage device in the second cart is charged via electrical contactbetween the second cart and the rack.
 18. The system of claim 15,wherein the energy storage device is a battery.
 19. The system of claim15, wherein the energy storage device is a capacitor.
 20. The system ofclaim 1, where in the dual shuttle is powered via electrical contactbetween the dual shuttle and the rack.
 21. The system of claim 1,wherein the second cart is powered so as to move along a row while thefirst cart moves along the aisle.
 22. A system for storing andretrieving items comprising: a rack including a plurality of layers,each layer including an aisle and a plurality of rows extending from theaisle, the items being storable in storage locations along the rows,each aisle having a loading position at one end and transfer positionslocated along the aisle adjacent ends of the rows; a shuttle on eachlayer, at least one of the shuttles being a dual shuttle including afirst cart movable along the aisle between the loading position and thetransfer positions, the dual shuttle including a second cart configuredto be carried by the first cart between the loading position and thetransfer positions, the second cart movable in either direction betweena transfer position and a storage location along a row while carrying anitem; a conveyor located on the first cart operable when the first cartis at the loading position to move the item onto or off the first cart;and a lift substantially adjacent the rack for lifting items to therespective loading positions for the layers, the lift including aplatform having a conveyor for moving items off the lift platform andtoward the loading positions of the respective layers.
 23. The system ofclaim 22, wherein each layer of the rack includes a conveyor adjacentthe loading position for transferring items from the lift platform tothe loading position.
 24. The system of claim 22, wherein the dualshuttle is powered by electrical contact between the dual shuttle andthe rack.
 25. The system of claim 22, wherein the second cart is poweredso as to move along a row while the first cart moves along the aisle.26. A system for storing and retrieving items comprising: a rackincluding a plurality of layers, each layer including an aisle and aplurality of rows extending from the aisle, the items being storable instorage locations along the rows, each aisle having a loading positionat one end and transfer positions located along the aisle adjacent endsof the rows; a shuttle on each layer, at least one of the shuttles beinga dual shuttle including a first cart movable along the aisle betweenthe loading position and the transfer positions, the dual shuttleincluding a second cart configured to be carried by the first cartbetween the loading position and the transfer positions, the second cartmovable in either direction between a transfer position and a storagelocation along a row while carrying an item, the second cart having araisable top platform, a first motor for moving the second cart alongthe rows and a second motor for selectively raising the top platform tolift an item; a conveyor located on the dual shuttle operable when thefirst cart is at the loading position to move the item onto or off thefirst cart; and a lift substantially adjacent the rack for lifting itemsto the respective loading positions for the layers, the lift including aplatform having a conveyor for moving items off the lift platform andtoward the loading positions of the respective layers.
 27. The system ofclaim 26, wherein the top platform can be lifted to remove an item fromthe first cart when the first and second carts are located at a transferposition so that the second cart can carry the item to a storagelocation in the respective row.
 28. The system of claim 26, wherein thetop platform can be lifted to retrieve an item from a storage locationin a row so that the second cart can carry the item to the first cart,the first cart then carrying the item to the loading position fortransfer out of the rack.
 29. The system of claim 26, wherein each layerof the rack includes a conveyor adjacent the loading position fortransferring items from the lift platform to the loading position. 30.The system of claim 26, wherein the second cart is powered so as to movealong a row while the first cart moves along the aisle.